1. Field of the Invention
Aspects of the present invention relate to an organic light emitting display device and a method for fabricating the same, and more particularly to an organic light emitting display device capable of preventing damage of signal lines and power lines for driving a pixel region, and a method for fabricating the same.
2. Description of the Related Art
In recent years, there have been many attempts to develop various flat panel displays that are lighter and smaller than cathode ray tubes. In particular, an organic light emitting display device having excellent luminous efficiency, luminance, viewing angle, and rapid response time has attracted public attention. The organic light emitting display device uses an organic light emitting diode (OLED) as an emissive diode. The organic light emitting diode includes an anode electrode, a cathode electrode, and an organic light emission layer arranged between the anode electrode and the cathode electrode. The organic light emission layer emits light by recombining holes and electrons, supplied from the anode electrode and the cathode electrode, to generate excitons.
FIG. 1 is a perspective view showing a conventional organic light emitting display device.
Referring to FIG. 1, an organic light emitting display (OLED) device 100 includes a device substrate 110 having a pixel region 140 and a scan driver 150 formed therein; an encapsulation substrate 120 arranged on the device substrate 110 to seal at least the pixel region 140; and a data driver 160 installed onto the device substrate 110 outside a sealing region of the encapsulation substrate 120. The sealing region is the region of the OLED device 100 that is disposed between the device substrate 110 and the encapsulation substrate 120 and sealed therein by a sealing agent 130.
The pixel region 140 includes a large number of pixels 145 formed on the device substrate 110. The pixels 145 are arranged regions in which scan lines (S) and data lines (D) cross. And, the pixels 145 are connected to one of the scan lines (S) and the data lines (D), respectively, and include at least an organic light emitting diode. Such pixels 145 generate light having a luminance corresponding to a data signal supplied from the data lines (D) when a scan signal is supplied from the scan lines (S) connected to the pixels 145. Therefore, the pixel region 140 displays an image.
Here, the pixels 145 include an organic light emission layer in which the organic light emitting diode, etc., is disposed. The organic light emission layer may easily deteriorate when oxygen or moisture penetrate therein. Accordingly, the pixel region 140 with the pixels 145 formed therein should be sealed to prevent the penetration of oxygen and moisture.
The scan driver 150 is driven by scan control signals supplied from a device outside the OLED device 100, such as a clock signal, a start pulse, an output enable signal, etc., to generate scan signals. The scan signals generated in the scan driver 150 are supplied to the pixel region 140 through the scan lines (S). If at least one transistor is formed in the pixel region 140, the scan driver 150 is formed on the device substrate 110 together with the transistor, and therefore sealed together with the pixel region 140. However, the scan driver 150 may be installed outside the sealing region in a chip form.
The encapsulation substrate 120 is arranged on the device substrate 110 to be overlapped with the pixel region 140, thereby to seal at least the pixel region 140. At this time, a sealing agent 130, such as epoxy resin, frit and the like, is formed in an edge of the encapsulation substrate 120. And, the device substrate 110 and the encapsulation substrate 120 are fused by the sealing agent 130 to seal a space therebetween. The encapsulation substrate 120 is scribed so a portion of the encapsulation substrate 120 may be removed and the encapsulation substrate 120 does not overlap a region in which a data driver 160 is installed. The data driver 160 may be installed in a chip form.
The data driver 160 generates data signals to correspond to data and control signals supplied from a device, or a data control unit, external to the OLED device 100. The data signal generated in the data driver 160 is supplied to the pixel region 140 through the data lines (D). The data driver 160 is installed onto the device substrate 110 in a region other than the sealing region after a general sealing process. However, the data driver 160 is not limited thereto. The data driver 160 may be formed on the device substrate 110 together with the pixels 140 and arranged inside the sealing region.
In the case of the above-mentioned conventional OLED device 100, at least one region of the data lines (D) is formed outside the sealing region. Thus, the data lines (D) extend across or through the sealing region as the data lines (D) are formed to connect the data driver 160 to the pixels 145 in the pixel region 140.
In order to prevent corrosion of the data lines (D) that extend out of the sealing region, at least one inorganic insulator is generally formed on the data lines (D).
For example, inorganic insulators 230 and 240 are formed on the data lines 220 to prevent moisture from corroding the data lines 220.
FIG. 2 is a cross-sectional view showing a portion of the OLED device 100 taken along a region “A” of FIG. 1. Data lines and their protective layers are shown in FIG. 2, and only the data lines and the protective layers are shown herein to the exclusion of other wires and insulators.
Referring to FIG. 2, the inorganic insulators 230 and 240 are formed on the data lines 220.
The inorganic insulators 230 and 240 are formed of an interlayer insulator 230 and an inorganic planarization layer 240. And, the inorganic insulators 230 and 240 are formed together with the pixel region 140.
Such inorganic insulators 230 and 240 protect the data lines 220. However, the inorganic insulators 230 and 240 are formed to partially overlap the sealing agent 130 such that the sealing agent 130 is disposed on the surface of the inorganic insulators 230 and 240. And the inorganic insulators 230 and 240 are formed of only inorganic materials as oxygen and moisture may penetrate the sealing region via the organic materials if the organic materials are included in the inorganic insulators 230 and 240.
However, the inorganic insulators 230 and 240 formed only in the pixel region cannot sufficiently protect the data lines 220 that extend from the pixel region to the data driver 160 from the penetration of oxygen and moisture.
Further, the inorganic insulators 230 and 240 formed on the data lines 220may not effectively protect the data lines 220 when the encapsulation substrate 120 is scribed.
More particularly, the inorganic insulators 230 and 240 may be easily broken by external impacts inflicted during a process for scribing and separating the encapsulation substrate 120. When the inorganic insulators 230 and 240 are broken during scribing and separating of the encapsulation substrate 120, the data lines 220 may be corroded as moisture penetrates cracks in the broken inorganic insulators 230 and 240. As a result, some of the data lines 220 are opened, resulting in poor emission of light from and display of images on the OLED device 100. Reliability testing, carried out at high temperatures and moisture contents, exposes weaknesses of the inorganic insulators 230 and 240.
In addition to damage to the data lines 220, power lines supply power from sources outside of the pixel region 140 to the pixel region 140 and the scan driver 150 may be damaged due to inadequate protection; and signal lines to supply scan control signals from a source, or scan control unit, outside of the pixel region 140 to the scan driver 150 disposed in the pixel region 140 may be damaged as the signal lines may be arranged beneath the scribing line of the encapsulation substrate 120.
FIG. 3A to FIG. 3D are diagrams showing a method for fabricating the organic light emitting display device as shown in FIG. 1.
Referring to FIG. 3A to FIG. 3D, to fabricate the organic light emitting display (OLED) device 100 as shown in FIG. 1, the pixels 145, the scan lines (S), the data lines (D), and the scan driver 150 are formed first on the device substrate 110 (FIG. 3A).
Then, the encapsulation substrate 120, coated with the sealing agent 130, is arranged on the device substrate 110, and then a sealing process is performed. The sealing agent 130 is disposed along an inside edge of the scribing line 310 of the encapsulation substrate 120 so that the sealing agent 130 seals the encapsulation substrate 120 about the pixel region 140. The sealing agent 130 is formed to seal at least the pixel region 140 (FIG. 3B).
Then, a process for scribing the encapsulation substrate 120 is carried out along the scribing line 310, and a removal region (120-1) is separated (FIG. 3C) leaving behind the portion of the encapsulation substrate 120 that covers the sealing region.
Then, a data driver 160 is installed on the exposed device substrate 110 outside of the sealing region and is connected to ends of the data lines (D) (FIG. 3D).
In the fabricating process of the above-mentioned OLED device 100, the inorganic insulators 230 and 240 may be broken as the inorganic insulators 230 and 240 on the data lines 220 collide with the removal region (120-1) when the removal region (120-1) of the encapsulation substrate 120 is separated as shown in FIG. 3C. The inorganic insulators 230 and 240 do not effectively protect signal lines and power lines such as the data lines 240 and the like from such impact, resulting in some of the signal lines or the power lines such as the data lines 240 and the like being exposed during the reliability testing at high temperatures and moisture.